K2.4 Variation, inheritance and evolution

Abstract

Variation, Inheritance and Evolution are explicitly detailed in the Science National Curriculum. This article focuses on material that will be useful for introducing these topics to both primary and secondary trainees who may themselves have very different previous experiences with this subject. A PowerPoint presentation as a download provides some ideas for this purpose.

It is recognised that for some the topic may be controversial and may appear to conflict with issues of religious belief. A range of children's' ideas are considered and a possible sequence for teaching the material is provided.

This is one of 17 articles whose main aim is to support the processes of teaching/learning between the science education tutor and the trainee science teachers with a focus on “teachers’ knowledge and understanding”. During a primary or secondary BEd, PGCE or GTP we hope that those learning to become science teachers will be able to challenge their own understanding of science and scientific concepts. Unit K0 specifically explores general issues relating to all the knowledge units - to the learning of science.

Standards: This unit specifically addresses Q14 but, appropriately used can contribute to and provide evidence of competence for many others of the standards especially Q4,6,7,8,18, 22 and 25.

Key words: Variation, Inheritance, Evolution, Intelligent design.

Contents

1.0 Introduction

A few primary teachers will have completed some post 16 study or even have a degree in biology, and about half of the secondary science teachers will have a degree with some biology content. However that means that a substantial number of trainee teachers of both primary and secondary phases will have an understanding of Biology equivalent only to a grade C at GCSE. The aim of these five ‘biology’ units is to provide support for these trainees (via their tutors) so that they can either teach to GCSE level, or acquire an understanding at that level so they have the confidence to teach at primary school. The emphasis is on the conceptual changes needed by learners (tutors, teachers and their pupils) to come to an understanding of living things.

The English National Curriculum once spelt out this genetics section in some detail, even at KS4, but this detail is only found in exam board syllabuses now.

Variation ... about environmental and inherited causes of variation within a species

Classification ... to classify living things into the major taxonomic groups

Inheritance ... that selective breeding can lead to new varieties.

Young children, like many people in the past, tend to accept that we have always been, this is how we are. The concept of evolution is hard to grasp at first. Once accepted, the mechanisms of evolution that scientists are beginning to work out become easier to comprehend. It is important that our intending teachers are aware of this conceptual development, so it is not enough just to understand the biological concepts, but also they need to know how children get to change their naïve outlook towards this deeper scientific model.

2.0 The conceptual barriers to understanding

Children's misconceptions about causes of variation:

Young children do not realise the causes of variation - they may think living things are different because they are ‘just born/grow that way’ or ‘God made them that way’

Older children often believe that variation results from environmental change - plants ‘change’ to suit the environment, or some people are tall because they have eaten a lot of food

The Lamarkian view that environmental change can be inherited: eg if a dog looses its tail, its puppies may be born tail-less

Children's misconceptions about time in relation to the age of things:

Young children often do not realise that something could be very much older than them. They often judge the age of things by appearances

When discussing past life forms, older children often mix fact with fantasy - dinosaurs are frequently associated with cavemen, who are given as the cause of the dinosaurs’ extinction

This section raises the issue of Evolution vs Creationism and the possible conflict between science teaching and some religious beliefs. There is usually a discussion taking place somewhere on the ASE website: http://www.upd8.org.uk/blog.php?blogid=34

3.0 Progression in children's ideas

Children are exposed to ideas about genetics and evolution only gradually as they get older. Even so they will pick up naïve ideas which we need to take into account as we try to help them develop a deeper understanding of genetics and evolution.

In the primary school they become aware of the differences between people, but they also need to realise that we are all very similar, and this similarity extends through the whole of life.

As their sense of time past develops, so children can begin to appreciate the story of life on this planet. Fossils and dinosaurs help. Selective breeding which leads to so many types of dog can be used to introduce natural selection as a mechanism of evolution.

4.0 A possible teaching sequence

This suggests some issues that tutors might want to share with their trainee teacher, both primary and secondary during their ‘college’ session. The text is in download 4 and the discussion is supported by the PowerPoint presentation of download 2.

Access the Teaching Resources section of the Bio-rad web site to find PowerPoint presentations created for hands-on, inquiry-driven Biotechnology Explorer workshop series. These PowerPoint presentations and laboratory quick guides are available for educational use only.

Download 5 Ideas for schools has some suggestions for intending primary teachers for activities suitable for use in school. Some of these are worth doing with the trainee teachers in college sessions to give them a flavour of the school activities. Although practical work is important in school it is probably more important that intending teachers think about what they hope their pupils will learn from the practical work they do, rather than simply carrying it out themselves. After all most of them have had the experiences, but they are unlikely to have thought about the way children’s ideas can be challenged during the practical work they do.

Secondary school intending teachers will have plenty of opportunity in school to observe and try out the various practical experiences pupils in school will have, so once again the important thing in ‘college’ sessions is to allow them to reflect on what purpose the practical work serves.

6.0 Useful References

http://evolution.berkeley.edu/evolibrary/home.phpUnderstanding Evolution is a non-commercial, education website, teaching the science and history of evolutionary biology. It’s aim is to help you understand what evolution is, how it works, how it factors into your life, how research in evolutionary biology is performed, and how ideas in this area have changed over time. The site is a collaborative project of the University of California Museum of Paleontology and the National Center for Science Education . (note the US spellings)

Littledyke, M., Ross, K., and Lakin, L.(2000) Science Knowledge and the Environment, London. David Fulton. (Chapter 8 gives some background information about human evolution and an explanation about the development of modern day wheat.)